Chip mounting apparatus and method of manufacturing semiconductor device

Abstract

Provided is a chip mounting device and a method for manufacturing a semiconductor device, which can improve the consistency of the imaging conditions of multiple imaging objects. The chip mounting device includes: multiple imaging devices, which are fixedly arranged in a column along the width direction of a substrate above a conveyance path; and a control unit configured to use the multiple imaging devices to image multiple imaging objects, which are located above the substrate in a column along the width direction. The control unit is configured to acquire images by imaging a board for image synthesis having multiple reference marks using the multiple imaging devices, perform image transformation so that the acquired images become a predetermined image, and save parameters at the time of performing the image transformation.

Description

Technical Field

[0001] This invention relates to a chip mounting apparatus, for example, a chip mounting machine that uses multiple recognition cameras to capture images of the accessory area. Background Technology

[0002] A chip mounting machine, as a chip mounting apparatus, is a device that uses resin paste, solder, gold plating, or other bonding materials to mount (place and bond) semiconductor chips (hereinafter referred to as bare chips) onto substrates such as wiring boards and lead frames, or onto already mounted bare chips. For example, in a chip mounting machine that mounts bare chips onto the surface of a substrate, the following actions (operations) are repeatedly performed: using a suction nozzle called a collet mounted at the front end of the mounting head to pick up the bare chip from the wafer and place it at a predetermined position on the substrate, applying pressure while heating the bonding material, thereby performing the mounting.

[0003] For example, when resins are used as bonding materials, resin pastes such as Ag epoxy resin and acrylic resin are used as adhesives (hereinafter referred to as paste adhesives). The paste adhesive for bonding the bare die to the substrate is sealed in a syringe, which moves up and down relative to the substrate and ejects the paste adhesive for application. That is, a predetermined amount of paste adhesive is applied to a predetermined location using a syringe containing the paste adhesive, and the bare die is pressed / baked to bond it to the paste adhesive. An identification camera (pre-forming camera) is installed near the syringe. This camera is used to confirm and position the applied paste adhesive, and to confirm that the applied paste adhesive is applied in a predetermined shape and only in a predetermined amount to the predetermined location.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-197277 Summary of the Invention

[0007] When using a single camera device to photograph multiple objects, there is a situation where the camera is tilted to photograph objects that are far away from directly below the camera device, which reduces the accuracy of positioning or visual inspection.

[0008] The objective of this invention is to provide a technique that improves the consistency of shooting conditions for multiple subjects. Other objectives and novel features can be understood from the description and accompanying drawings in this specification.

[0009] The following is a brief summary of a representative solution in this invention.

[0010] That is, the chip mounting apparatus includes: a plurality of camera devices fixedly arranged in a row above a transport path along the width direction of a substrate; and a control unit configured to use the plurality of camera devices to photograph a plurality of photographed objects, the plurality of photographed objects being arranged in a row on the substrate along the width direction. The control unit is configured to acquire images by using the plurality of camera devices to photograph a board for image compositing with a plurality of reference marks, to perform image transformation in a manner that makes the acquired images conform to a predetermined image, and to save the parameters used during the image transformation.

[0011] Invention Effects

[0012] The chip mounting device described above can improve the consistency of shooting conditions for multiple subjects. Attached Figure Description

[0013] Figure 1 This is a schematic top view illustrating the chip placement machine in the embodiment.

[0014] Figure 2 This means that in Figure 1 The diagram shows the movement of the pickup head and the placement head when viewed from the direction of arrow A.

[0015] Figure 3 It is shown Figure 1 A schematic cross-sectional view of the main parts of the bare chip supply section shown.

[0016] Figure 4 It is shown Figure 1 The diagram shown is a schematic representation of the control system of a chip mounting machine.

[0017] Figure 5 It shows the use Figure 1 The flowchart shown is a process for manufacturing semiconductor devices using a chip mounting machine.

[0018] Figure 6 This diagram illustrates the ideal scenario when multiple cameras are used in multi-camera shooting.

[0019] Figure 7 This diagram illustrates the less-than-ideal situation when using multiple cameras in multi-camera shooting.

[0020] Figure 8 This is a top view showing the plate used for image composition.

[0021] Figure 9 This is a side view showing the camera and the plate used for image synthesis.

[0022] Figure 10 This is a diagram illustrating the method for correcting installation errors.

[0023] Figure 11This is a side view showing the camera and the panel used for brightness correction.

[0024] Figure 12 This is a conceptual diagram illustrating the camera's sensitivity error correction process.

[0025] Figure 13 This is a side view showing the camera and the substrate.

[0026] Figure 14 This is a diagram illustrating the image synthesis method.

[0027] The reference numerals in the attached figures are explained as follows:

[0028] 8 Control Department

[0029] 10. Chip Placement Machine (Chip Placement Device)

[0030] 52. Transport Channel (Transport Path)

[0031] 101-103 Pre-formed cameras (video recording devices)

[0032] 121 Image Composition Board

[0033] Subjects photographed in OB1-OB3

[0034] P Attachment Area

[0035] S substrate Detailed Implementation

[0036] The embodiments are described below using the accompanying drawings. Furthermore, in the following description, the same reference numerals are sometimes used to refer to the same constituent elements, and repeated descriptions are omitted. Additionally, to make the description clearer, the width, thickness, shape, etc., of various parts of the drawings are sometimes shown schematically compared to the actual form; however, this is merely an example and not a limitation on the interpretation of the invention.

[0037] use Figure 1 and Figure 2 The configuration of the chip mounting machine in the implementation method is described. Figure 1 This is a schematic top view illustrating the chip placement machine in the embodiment. Figure 2 Explanation in Figure 1 The diagram shows the movement of the pickup head and the placement head when viewed from the direction of arrow A.

[0038] The chip mounter 10 generally includes a bare chip supply unit 1 for supplying bare chips D to be mounted on a substrate S, a pick-up unit 2, an intermediate stage unit 3, a preforming unit 9, a mounting unit 4, a transport unit 5, a substrate supply unit 6, a substrate removal unit 7, and a control unit 8 for monitoring and controlling the operation of each unit. The Y-axis direction is the front-to-back direction of the chip mounter 10, and the X-axis direction is the left-to-right direction. The bare chip supply unit 1 is located near the front of the chip mounter 10, and the mounting unit 4 is located further away. Here, multiple product areas (hereinafter referred to as accessory areas P) are formed on the substrate S as the last package. For example, when the substrate S is a lead frame, the accessory areas P have connector tabs for mounting the bare chips D.

[0039] First, the bare die supply unit 1 supplies a bare die D mounted to the attachment region P of the substrate S. The bare die supply unit 1 includes a wafer holding stage 12 that holds a wafer 11 and a stripping unit 13 (shown in dashed lines) that pushes the bare die D off the wafer 11. The bare die supply unit 1 moves along the XY axis under the action of a drive mechanism (not shown), moving the bare die D to be picked up to the position of the stripping unit 13.

[0040] The pickup unit 2 includes a pickup head 21 for picking up a bare die D, a Y-drive unit 23 for moving the pickup head 21 along the Y-axis, various drive units (not shown) for raising, rotating, and moving the collet 22 along the X-axis, and a die recognition camera 24 for controlling the pickup position of the bare die D picked up from the die 11. The pickup head 21 has a collet 22 that holds the pushed-up bare die D at its front end, picking up the bare die D from the bare die supply unit 1 and placing it on the intermediate stage 31. The pickup head 21 has various drive units (not shown) for raising, rotating, and moving the collet 22 along the X-axis.

[0041] The intermediate stage 3 has an intermediate stage 31 for temporarily mounting the bare chip D and a stage recognition camera 32 for recognizing the bare chip D on the intermediate stage 31.

[0042] The preforming unit 9 includes an syringe 91, a drive unit 93 for moving the syringe 91 along the Y-axis and vertically, and a preforming camera 94, which acts as an imaging device to control the application position of the syringe 91. Details of the preforming camera 94 will be described later. The preforming unit 9 uses the syringe 91 to apply a paste-like adhesive, such as epoxy resin, to the substrate S transported by the transport unit 5. The syringe 91 is configured to have a paste-like adhesive internally sealed, and uses air pressure to extrude the paste-like adhesive from the nozzle tip and apply it to the substrate S. When the substrate S, for example, has multiple unit lead frames arranged laterally in a row and a continuous series of multi-connected lead frames, the paste-like adhesive is applied to each connector piece of the unit lead frame.

[0043] The mounting unit 4 picks up a bare die D from the intermediate stage 31 and mounts it onto the attachment area P of the transported substrate S, which is coated with a paste adhesive. The mounting unit 4 includes: a mounting head 41, which, like the pickup head 21, has a collet 42 that holds the bare die D at its front end; a Y-drive unit 43 that moves the mounting head 41 along the Y-axis; and a substrate recognition camera 44 that captures a position recognition mark (not shown) on the attachment area P of the substrate S and identifies the mounting position. With this configuration, the mounting head 41 corrects the pickup position / orientation based on the image data from the stage recognition camera 32, picks up the bare die D from the intermediate stage 31, and mounts the bare die D onto the substrate based on the image data from the substrate recognition camera 44.

[0044] The transport unit 5 has a substrate transport claw 51 for gripping and transporting a substrate S and a transport channel 52 that serves as a transport path for the substrate S to move. The substrate S is moved by a ball screw (not shown) that drives a nut (not shown) of the substrate transport claw 51 provided in the transport channel 52. With this configuration, the substrate S moves from the substrate supply unit 6 along the transport channel 52 to the mounting position, and after mounting, moves to the substrate removal unit 7, where the substrate S is delivered.

[0045] Next, use Figure 3 Explain the structure of bare chip supply unit 1. Figure 3 It is shown Figure 1 A schematic cross-sectional view of the main parts of the bare chip supply section shown.

[0046] The bare die supply unit 1 includes a wafer holding stage 12 that moves horizontally (XY axis direction) and a stripping unit 13 that moves vertically. The wafer holding stage 12 has an extension ring 15 that holds a wafer ring 14 and a support ring 17 that horizontally positions a dicing tape 16 fixed to the wafer ring 14. The bare die D, which is cut in a mesh pattern in the wafer 11, is bonded and fixed to the dicing tape 16. The stripping unit 13 is disposed inside the support ring 17.

[0047] When the bare die D is pushed upward, the bare die supply unit 1 lowers the extension ring 15 of the holding wafer ring 14. As a result, the dicing strip 16 held by the wafer ring 14 is stretched, the spacing of the bare dies D is increased, and the dicing strip 16 is pushed upward from below the bare die D or moved horizontally by the stripping unit 13, thereby improving the pickability of the bare die D.

[0048] use Figure 4 Explain the control system of the chip mounting machine 10. Figure 4 It is shown Figure 1 The diagram shown is a schematic representation of the control system of a chip mounting machine.

[0049] like Figure 4As shown, the control system 80 includes a control unit 8, a drive unit 86, a signal unit 87, and an optical system 88. The control unit 8 generally includes a control / computation unit 81 mainly composed of a CPU (Central Processing Unit), a storage unit 82, an input / output unit 83, a bus 84, and a power supply unit 85. The storage unit 82 includes a main storage unit 82a composed of RAM storing processing programs, and an auxiliary storage unit 82b composed of HDD storing control data, image data, etc., required for control. The input / output unit 83 includes a monitor 83a displaying device status and information, a touch panel 83b for inputting operator instructions, a mouse 83c for operating the monitor, and an image acquisition unit 83d for acquiring image data from the optical system 88. Additionally, the input / output device 83 includes: a motor control device 83e, which controls the drive unit 86 of the XY stage (not shown) of the bare die supply unit 1, the ZY drive axis of the placement head stage, etc.; and an I / O signal control device 83f, which acquires or controls signals from various sensor signals, switches, and other signal units 87 from lighting devices, etc. Figure 1 or Figure 2 The chip recognition camera 24, preform camera 94, stage recognition camera 32, and substrate recognition camera 44 are shown. The control / computing device 81 acquires the required data via the bus 84 and performs calculations to control the mounting head 41, etc., or sends information to the monitor 83a, etc.

[0050] The control unit 8 stores the image data captured by the optical system 88 in the storage device 82 via the image acquisition device 83d. Using software based on the stored image data, the control / computing unit 81 performs positioning of the bare chip D and substrate S, checks the coating pattern of the adhesive paste, and inspects the surfaces of the bare chip D and substrate S. Based on the positions of the bare chip D and substrate S calculated by the control / computing unit 81, the drive unit 86 is moved according to the software and by means of the motor control device 83e. This process positions the bare chip D on the wafer 11, and the drive units of the bare chip supply unit 1 and the chip mounting unit 4 move the bare chip D, mounting it onto the substrate S. The recognition camera used in the optical system 88 is a grayscale camera, a color camera, etc., which quantifies brightness (light intensity).

[0051] Next, use Figure 5 This describes a method for manufacturing semiconductor devices using a chip mounting machine according to an embodiment. Figure 5 It shows the use Figure 1 The flowchart shown is a process for manufacturing semiconductor devices using a chip mounting machine.

[0052] (Step S51: Wafer / Substrate Handling Process)

[0053] The wafer ring 14, with the dicing tape 16 attached to the bare die D separated from the wafer 11, is stored in a wafer cassette (not shown) and transferred into the die mounter 10. The control unit 8 supplies the wafer ring 14 from the wafer cassette filled with the wafer ring 14 to the bare die supply unit 1. Additionally, the substrate S is prepared and transferred into the die mounter 10. The control unit 8 uses the substrate supply unit 6 to mount the substrate S onto the substrate transport claw 51.

[0054] (Step S52: Pick-up process)

[0055] The control unit 8 uses the wafer holding stage 12 to move the wafer ring 14 in a manner capable of picking up the desired bare die D from the wafer ring 14, and performs positioning and surface inspection based on data captured by the wafer recognition camera 24. The control unit 8 uses the peeling unit 13 to peel the positioned bare die D from the dicing tape 16. At the same time, the control unit 8 lowers the pick-up head 21 to directly above the bare die D to be picked up, and uses the collet 22 of the pick-up head 21 to vacuum-adsorb the bare die D peeled from the dicing tape 16. Then, the control unit 8 causes the pick-up head 21 to perform an upward movement, a parallel movement, and a downward movement, placing the bare die D at a predetermined position on the intermediate stage 31. At this time, the control unit 8 uses the suction hole (not shown) of the intermediate stage 31 to adsorb the bare die D and separate it from the pick-up head 21. In this way, the bare die D peeled from the dicing tape 16 is adsorbed and held by the collet 22 and transported and placed on the intermediate stage 31.

[0056] The control unit 8 uses the stage recognition camera 32 to photograph the bare chip D on the intermediate stage 31 and performs positioning and surface inspection of the bare chip D. The control unit 8 calculates the offset (X, Y, θ directions) of the bare chip D on the intermediate stage 31 relative to the bare chip position reference point of the chip placement machine through image processing. Furthermore, the bare chip position reference point is pre-set to a predetermined position on the intermediate stage 31 as the initial setting of the device. Then, the control unit 8 performs surface inspection of the bare chip D through image processing.

[0057] Then, the control unit 8 returns the pick-up head 21, which has transported the bare chip D to the intermediate stage 31, to the bare chip supply unit 1. Following the above steps, the next bare chip D is peeled off from the dicing tape 16, and then the bare chips D are peeled off from the dicing tape 16 one by one in the same manner.

[0058] (Step S53: Mounting process)

[0059] The control unit 8 uses the pre-forming camera 94 to acquire an image of the surface of the substrate S before coating and confirms the surface to be coated with the paste adhesive. If there are no problems with the surface to be coated, the control unit 8 applies the paste adhesive from the syringe 91 to the substrate S transported by the transport unit 5. In the case that the substrate S is a multi-lead frame, the paste adhesive is applied to all connector tabs. After coating, the control unit 8 uses the pre-forming camera 94 again to confirm whether the paste adhesive is correctly applied and inspects the applied paste adhesive.

[0060] If the coating process is successful, the control unit 8 uses the transport unit 5 to transport the substrate S to the mounting stage BS. Then, the control unit 8 uses the substrate recognition camera 44 to photograph the substrate S placed on the mounting stage BS. The control unit 8 calculates the offset (X, Y, θ directions) of the substrate S relative to the substrate position reference point of the chip mounter through image processing. Furthermore, regarding the substrate position reference point, the predetermined position of the substrate inspection unit is maintained in advance as the initial setting of the device.

[0061] The control unit 8 adjusts the adsorption position of the mounting head 41 based on the offset of the bare chip D calculated in step S52, and uses the clamp 42 to adsorb the bare chip D. The mounting head 41, with the bare chip D adsorbed, rises, moves horizontally, and falls from the intermediate stage 31, placing the bare chip D onto a predetermined location on the substrate S on the mounting stage BS. Then, the control unit 8 checks whether the bare chip D has been mounted to the desired position based on image data captured by the substrate recognition camera 44.

[0062] (Step S54: Substrate removal process)

[0063] The control unit 8 transports the substrate S with the bare chip D mounted on it to the substrate removal unit 7. The control unit 8 uses the substrate removal unit 7 to remove the substrate S with the bare chip D mounted on it from the substrate transport claw 51. The substrate S is then removed from the chip mounter 10.

[0064] As described above, the bare die D is mounted on the substrate S and removed from the die mounter. Then, in the wire bonding process, it is electrically connected to the electrodes of the substrate S via Au wires or the like. Afterwards, the substrate S is transported to the injection molding process, where the bare die D and the Au wires are sealed with injection molding resin (not shown), thereby completing the encapsulation.

[0065] In this embodiment, the pre-forming camera 94 is used for the visual inspection of paste adhesives, etc. First, to make this embodiment clearer, the problems with cameras such as the pre-forming camera 94 will be explained.

[0066] Generally, with a fixed number of camera pixels, increasing the field of view using a lens increases pixel resolution. Therefore, if the size of the substrate S increases, and consequently the field of view increases, the camera's pixel resolution becomes insufficient for visual inspection.

[0067] Furthermore, if a microlens, acting as a non-telecentric lens, is used to increase the field of view (wide field of view), then when the subject (object being photographed) is a three-dimensional object such as a paste adhesive, the area of ​​the object being photographed will differ between objects directly below the camera (lens) and objects at the edge of the field of view, or the sides of objects at the edge of the field of view may be visible. Telecentric lenses, by focusing parallel light, prevent the entire side of the object from being seen. However, this requires larger lenses, which in turn increases the focal distance. From an efficiency standpoint, mounting such large lenses in a chip mounting device is not preferable.

[0068] By utilizing multiple cameras (lenses) to divide the field of view across the width of the cover substrate S, the magnification of each camera can be increased, thereby improving pixel resolution. Furthermore, by positioning the cameras (lenses) directly above the application area of ​​the paste adhesive, even microlenses can achieve a more uniform appearance.

[0069] Therefore, in order to improve pixel resolution and reduce the measurement area error when photographing the paste adhesive as a three-dimensional object from directly above, a scheme was studied to construct the pre-forming camera 94 in this embodiment by arranging multiple cameras side by side (multi-camera shooting). Here, for the sake of simplicity, the paste adhesive applied to the object being photographed is set to a rectangular shape.

[0070] use Figure 6 This indicates that the footage was shot using multiple cameras. Figure 6 This diagram illustrates the ideal scenario when multiple cameras are used in multi-camera shooting. Figure 6 (a) is a stereoscopic view showing the camera and the subject being photographed. Figure 6 (b) is a diagram showing the images captured by each camera. Figure 6 (c) shows that Figure 6 The image is a composite image obtained by simply stitching together the images in (b).

[0071] For example, such as Figure 6 As shown in (a), above the substrate S, a plurality of cameras 101-103 are arranged and fixed in a row along the width direction (Y-axis direction) of the substrate S. These cameras 101-103 are spaced at predetermined intervals in the horizontal direction at the same height, and the optical axes of each camera 101-103 are parallel to each other and perpendicular to the substrate S. Each camera 101-103 is equipped with a lens 111-113. The fields of view of adjacent cameras overlap. Here, the substrate S is, for example, rectangular and flat, and has a plurality of accessory areas arranged longitudinally and transversely. Figure 6 In (a), an example is shown where a column of the substrate S has three accessory areas, showing three objects to be photographed: OB1, OB2, and OB3. Furthermore, a coaxial illumination (not shown) is provided below the cameras 101-103 (lenses 111-113).

[0072] Each camera 101-103 simultaneously (in parallel) photographs objects OB1, OB2, and OB3. Furthermore, by transporting the substrate S along the transport direction (X-axis) using the transport channel 52, the remaining columns of objects are photographed sequentially. Multi-camera shooting allows for shooting from approximately directly above the objects, improving the uniformity of inspection. Additionally, multi-camera shooting eliminates the need to move the cameras, achieving the same processing efficiency as a wide-field-of-view optical system.

[0073] In multi-camera setups, such as Figure 6 As shown in (c), from Figure 6 The images output by each camera 101 to 103 shown in (b) are combined into a single large image and processed in the same coordinate system.

[0074] However, multi-camera shooting has the following problems.

[0075] (A) If multiple cameras have their own installation errors (X, Y, Z, θ, attitude), the composite image will be distorted if the images are simply stitched together.

[0076] (B) When there are differences in camera sensitivity and individual lens variations, even when photographing the same object, differences in brightness will occur between the output images. Since the appearance inspection of adhesive pastes and the like is based on brightness relative to the image, errors will occur in different cameras and lenses with individual variations, making it impossible to obtain high-precision images.

[0077] use Figure 7 Explain the problem in (A) above. Figure 7 This diagram illustrates a situation where multiple cameras are not ideal in multi-camera shooting. Figure 7 (a) is a stereoscopic view showing the camera and the subject being photographed. Figure 7 (b) is a diagram showing the images captured by each camera. Figure 7 (c) shows that Figure 7 The image is a composite image obtained by simply stitching together the images in (b).

[0078] For example, in Figure 7 In (a), camera 101 has installation errors in its position (X position) along the X-axis, position (Y position) along the Y-axis, position (Z position) along the Z-axis, and position (rotation) along the θ-axis; camera 102 has installation errors in its attitude (optical axis) tilt; and camera 103 is ideal and has no installation errors. The result is as follows: Figure 7As shown in (b), the image from camera 101 becomes an image shifted to the left and rotated to the left, the image from camera 102 becomes a trapezoidal image shifted to the right, and the image from camera 103 is... Figure 6 The same image. If these images are simply stitched together, they become... Figure 7 The composite image shown in (c) is... Figure 6 The synthesized image shown in (c) is different.

[0079] Therefore, in this embodiment, in order to solve the problem mentioned in (A) above, correction data is obtained using the image compositing board 121 at the time of chip placement machine 10 leaving the factory or during adjustment (tracking operation). By using this correction data, the accuracy of image compositing using images captured by multiple cameras can be improved more easily.

[0080] First, use Figures 8-10 This section explains how to correct camera mounting errors (mounting error correction processing). Figure 8 This is a top view showing the plate used for image composition. Figure 9 This is a side view showing the camera and the plate used for image synthesis. Figure 10 This diagram illustrates the process of correcting installation errors. Figure 10 (a) is a diagram showing the field of view of each camera and the board used for image synthesis. Figure 10 (b) is a diagram showing images taken using each camera. Figure 10 (c) is a diagram showing the transformed image. Figure 10 (d) is a diagram showing the synthesized image.

[0081] Prepare Figure 8 The image compositing plate 121 shown is printed with high precision the reference mark MK. Here, as... Figure 8 As shown, reference marker MK has 4 points in the fields of view IA1 to IA3 of cameras 101 to 103 respectively. Since the fields of view of adjacent cameras overlap, reference marker MK has 2 points in each overlapping part of the fields of view of adjacent cameras. In this way, reference marker MK is formed on the image compositing plate 121. When there are three cameras, reference marker MK with 8 points is formed on the image compositing plate 121. The reference marker MK serves as the reference for the input coordinates required for the projection transformation of the images output from each camera 101 to 103.

[0082] like Figure 9 As shown, the image compositing plate 121 is manually placed on the stage 130. Here, a substrate S, to which the object to be photographed is attached, is fixed on the stage 130. Alternatively, the image compositing plate 121 can be transported and placed using the transport unit 5, similar to the substrate S.

[0083] The control unit 8 has a plate 121 for image synthesis at the positions of four reference markers MK in the fields of view IA1 to IA3 of each of the camera devices 101 to 103. Figure 10 In (a), cameras 101 and 102 have installation errors. Camera 101 is installed by offsetting to the left in the X-axis direction, and camera 102 is installed by rotating to the right (clockwise) when viewed from above. Camera 103 has no installation error. As a result, the images P110, P120, and P130 of the image compositing board 121, which uses images captured by each of the cameras 101 to 103, become... Figure 10 The image shown in (b). For example, image P110 is an image captured by the image compositing plate 121 shifted to the right in the X-axis direction relative to the field of view IA1 of the camera 101.

[0084] like Figure 10 As shown in (b), the control unit 8 detects the position of each reference marker MK for each image P110, P120, and P130 through image processing such as marker or pattern matching. The control unit 8 performs image transformation by projecting the coordinates of the captured reference marker MK to the coordinates (reference coordinates) of the four corners of the image. Thus, it obtains... Figure 10 The three images P111, P121, and P131 are shown in (c). Here, the projection transformation can not only perform parallel translation, rotation, scaling, and cropping (deformation) using a 3x3 matrix, but also perform image transformation from trapezoidal to rectangular. In this embodiment, it is possible to transform the coordinates of four points of the input image into the coordinates of four points of the output image, and to transform an image taken at an angle into an image viewed from directly above (vertical correction).

[0085] Control Department 8 Figure 10 The images P111 to P113 shown in (c) are synthesized to obtain the result. Figure 10 The composite image P100 shown in (d) is the same as the reference image described above. The control unit 8 calculates and stores the parameters of the image transformation (transformation matrix) in the image of the board 121 used for image compositing captured by each of the cameras 101 to 103.

[0086] Furthermore, in this embodiment, to solve the problem described in (B) above, brightness correction data is acquired using a brightness correction board 122 during the manufacturing process of the chip mounter 10 or during adjustment (tracking operation). By using this correction data, the accuracy of image synthesis using images captured by multiple cameras can be improved more easily.

[0087] Next, use Figure 11 and Figure 12 This section describes a sensitivity calibration method based on camera gain correction (sensitivity error correction processing). Figure 11 This is a side view showing the camera and the panel used for brightness correction. Figure 12 This is a conceptual diagram illustrating the camera's sensitivity error correction processing. Figure 12 (a) is the composite image before camera gain correction. Figure 12 (b) is the composite image after camera gain correction.

[0088] A brightness correction plate 122 with uniform reflectivity is prepared. Here, the brightness correction plate 122 serves as a reference plate to ensure consistent output levels for each camera 101-103. The image compositing plate 121 can also be used as the brightness correction plate 122. Furthermore, as... Figure 11 As shown, the brightness correction plate 122 is manually placed on the stage 130 so that it enters the field of view of each camera 101-103. Alternatively, the brightness correction plate 122 can be placed using the transport unit 5, similar to the substrate S. The control unit 8 simultaneously captures images of the brightness correction plate 122 using each camera 101-103. Furthermore, the control unit 8 calculates an average output based on the output values ​​representing the brightness of multiple pixels in the central portion of each image output from each camera 101-103. Here, the central portion is, for example, an area where the fields of view of adjacent cameras do not overlap, i.e., an area in the image compositing plate 121 where the reference mark MK is not provided, and is a non-peripheral area. The control unit 8 determines the camera with the highest output value (the brightest camera) based on the average output level. The control unit 8 calculates (adjusts) the camera's gain value in a way that achieves the same output level as the brightest camera among cameras other than the brightest camera. The gain includes both analog gain and digital gain. The former refers to increasing the charge during the process of light exposed by the image sensor being converted into electrical charge, while the latter refers to increasing the value obtained through software calculation. Gain adjustment can be either one.

[0089] For example, in Figure 12 In (a), image P32 captured by camera 102 is darker than images P31 and P33 captured by cameras 101 and 103. Furthermore, image P31 captured by camera 101 is darker than image P33 captured by camera 103. Therefore, by adjusting the gain values ​​of cameras 101 and 102 to achieve the same brightness value as image P33 captured by camera 103, the following is obtained: Figure 12 The composite image shown in (b) is an example. Here, the correction is only applied to camera or lens factors.

[0090] Next, use Figure 13 and Figure 14 This describes the image synthesis process during continuous operation of the chip mounting machine 10. Figure 13 This is a side view showing the camera and the substrate. Figure 14 This is a diagram illustrating image synthesis methods. Figure 14 (a) is a diagram showing the field of view of each camera and the subject being photographed. Figure 14 (b) is a diagram showing images taken using each camera. Figure 14 (c) is a diagram showing the transformed image. Figure 14 (d) is a diagram showing the synthesized image.

[0091] The control unit 8 uses the transport unit 5 to transport the substrate S, and as follows: Figure 13 The objects are placed on the stage 130 so that they are within the field of view of each camera 101-103. Then, the control unit 8 uses each camera 101-103 to photograph the objects OB1-OB3. Here, the gain of each camera 101-103 is adjusted using the aforementioned sensitivity error correction processing. Figure 14 As shown in (a), with Figure 10 Similarly, in (a), cameras 101 and 102 have installation errors. Camera 101 is installed by offsetting it to the left in the X-axis direction, and camera 102 is installed by rotating it to the right (clockwise) when viewed from above. As a result, images P210, P220, and P230 of the subjects OB1 to OB3 captured by each of the cameras 101 to 103 become... Figure 14 Image (b) is shown.

[0092] Then, the control unit 8 uses the pre-saved image transformation parameters to perform image transformation through projection transformation and obtain... Figure 14 Images P211, P221, and P231 are shown in (c). This eliminates camera mounting errors. Furthermore, the control unit 8 stitches the transformed images together and acquires the data. Figure 14 The image shown in (d) (synthetic image P200) is subjected to subsequent processing (positioning, appearance inspection).

[0093] According to this embodiment, one or more of the following effects are achieved.

[0094] (1) It is possible to manage images acquired by multiple cameras at the same magnification and coordinates using simpler device configurations and fixtures (image synthesis plate 121).

[0095] (2) Images acquired by multiple cameras can be managed at the same level of brightness using a simpler device and fixture (plate 122 for brightness correction).

[0096] (3) By using multiple cameras (lenses) to divide the area for observation, the magnification of each lens can be increased, and the pixel resolution can be improved.

[0097] (4) It can capture three-dimensional objects roughly directly below the camera (lens) and avoid capturing the sides of the three-dimensional objects.

[0098] (5) It can stabilize the positioning accuracy of the object being photographed, and also stabilize the appearance inspection.

[0099] The invention proposed by the inventors of this application has been specifically described above based on the embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made.

[0100] For example, in one embodiment, an example is described where the number of reference markers MK that the image synthesis plate 121 enters the field of view of each camera is four, but it can also be five or more.

[0101] In addition, in the embodiment, an example is described in which the plate 121 for image synthesis is provided with a reference mark MK. Alternatively, instead of the reference mark MK, a line extending along the four sides that enters the field of view of each camera can be set.

[0102] Furthermore, in the implementation, an example of projection transformation as an image transformation is described, but affine transformation can also be used.

[0103] In addition, in the embodiment, an example of applying a paste-like adhesive to the substrate using a preforming section was described. However, instead of using a paste-like adhesive applied with syringe 91, a film-like adhesive material called a die-attachment film (DAF) can be used to bond the bare chip to the substrate. This film is attached between the wafer 11 and the dicing tape 16. The DAF is suitable for stacked packages formed by placing multiple bare chips on the bare chips on the substrate S. In this case, it is preferable to multiply the substrate recognition camera and the preforming camera and correct them to a board 121 for image synthesis and a board 122 for brightness correction. In addition, in this case, the substrate or the bare chip placed on the substrate can also be cleaned in the preforming section.

[0104] In addition, in the embodiment, an intermediate stage 3 is provided between the bare die supply section 1 and the mounting section 4. The bare die D picked up from the bare die supply section 1 using the pick-up head 21 is placed on the intermediate stage 31, and the bare die D is picked up again from the intermediate stage 31 using the mounting head 41 and mounted on the transported substrate S. Alternatively, the bare die D picked up from the bare die supply section 1 can be mounted on the substrate S using the mounting head 41.

Claims

1. A chip mounting apparatus, characterized in that, have: The transport path of the substrate; Multiple camera devices are fixedly arranged in a row above the transport path along the width direction of the substrate; and The control unit is configured to use multiple camera devices to capture images of multiple objects, the multiple objects being captured being arranged in a row along the width direction on the substrate. The control unit is configured such that, Images are acquired by using multiple camera devices to capture images of a plate with multiple reference marks for image compositing. The position of the captured reference marker is detected by image processing. Image transformation is performed by shifting the coordinates of the captured reference marks to reference coordinates located at the four corners of the image through projection transformation or affine transformation. Save the parameters used during the image transformation.

2. The chip mounting apparatus according to claim 1, characterized in that, The plurality of reference marks are formed on the plate for image synthesis in such a manner that each of the plurality of camera devices has 4 points in its field of view and 2 points in the overlapping part of the field of view of adjacent camera devices.

3. The chip mounting apparatus according to claim 1, characterized in that, The control unit is configured such that, Save the parameters of the transformation matrix used for the projection transformation or affine transformation.

4. The chip mounting apparatus according to claim 3, characterized in that, The control unit is configured such that, Based on the parameters, the images of the multiple captured objects are subjected to projection transformation or affine transformation respectively. The images obtained by the projection transformation or affine transformation are stitched together to generate a composite image.

5. The chip mounting apparatus according to claim 1, characterized in that, The control unit is configured such that, Images are acquired by photographing the brightness correction plate using the aforementioned camera device. The gain value of the camera device is adjusted based on the acquired image.

6. The chip mounting apparatus according to claim 5, characterized in that, The control unit is configured such that, The brightness of the imaging device is calculated based on the average brightness of the central portion of each image obtained from the image captured by the brightness correction plate. The brightest camera is determined based on the calculated brightness, and the gain values ​​of the other camera devices are adjusted to achieve the same brightness as the determined camera.

7. The chip mounting apparatus according to claim 6, characterized in that, The image synthesis plate is used as the brightness correction plate.

8. The chip mounting apparatus according to any one of claims 1 to 7, characterized in that, The control unit is configured to transport the substrate along its length and to capture images of multiple accessory areas in the next column using multiple camera devices.

9. The chip mounting apparatus according to any one of claims 1 to 7, characterized in that, The object being photographed is a paste-like adhesive applied to the substrate.

10. The chip mounting apparatus according to claim 9, characterized in that, The control unit is configured to perform visual inspection of the paste adhesive applied to the substrate using the camera device.

11. A method for manufacturing a semiconductor device, characterized in that, include: The process of moving a substrate into a chip mounting apparatus includes: a plurality of camera devices fixedly arranged in a row above a transport path along the width direction of the substrate; and a control unit configured to acquire images by taking pictures of a brightness correction board using the camera devices, adjust the gain value of the camera devices based on the acquired images, acquire images by taking pictures of an image compositing board with multiple reference marks using the plurality of camera devices with adjusted gain values, detect the position of the captured reference marks by image processing, perform image transformation by moving the coordinates of the captured reference marks to reference coordinates located at the four corners of the image through projection transformation or affine transformation, and save the parameters when performing the image transformation. The process of identifying the photographed object involves using multiple camera devices to photograph the photographed object in multiple accessory areas located on the substrate and along a column of width directions to obtain multiple images, generating a composite image based on the acquired multiple images, and identifying the photographed object based on the composite image. as well as The process of transporting the substrate along its length and using multiple camera devices to capture images of multiple accessory areas in the next column.

12. The method for manufacturing a semiconductor device according to claim 11, characterized in that, It also includes the following steps: saving the parameters of the transformation matrix used for the projection transformation or affine transformation.

13. The method for manufacturing a semiconductor device according to claim 12, characterized in that, It also includes the following steps: performing projection transformation or affine transformation on the images of the multiple objects to be photographed according to the parameters, and stitching the images obtained by the projection transformation or affine transformation together to generate a composite image.

14. The method for manufacturing a semiconductor device according to claim 11, characterized in that, It also includes the following steps: calculating the brightness of the camera device based on the average brightness of the central portion of each image obtained by shooting the brightness correction plate, determining the brightest camera device based on the calculated brightness, and adjusting the gain values ​​of the other camera devices to achieve the same brightness as the determined camera device.

15. The method for manufacturing a semiconductor device according to any one of claims 11 to 14, characterized in that, It also includes the step of applying a paste adhesive to the substrate. The object being photographed is the applied paste-like adhesive.

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